Suppose your organization uses the Class B network ID of 172.20.0.0 for its entire network and wants to create 15 subnets. What is the subnet increment (the book refers to this as the magic number) you can use to calculate the network IDs?

16

Explanation:

The mask of a Subnet can be used to identify the specific IP address of any type of Subnets. It is essential to know the location of a given IP address. This is widely used to track those that are involved in criminal activities. It is commonly used by security agencies such as police, detectives, etc. The number of network IDs is about (15+1) = 16.

16 subnets

Explanation:

A network is a connection of computer devices, meant to communicate and shares peripheral resources. The computer or end devices in a network uses a Mac address and an IP address to implement communication.

The IP address has two versions, they are IP version 4 and 6. The ipv4 is a 32 bits address of 4 octet divided by dots. The class B network address has a network id of 255 on the first two octet.

To get 15 subnet from the 172.20.0.0, four bits are borrowed from the third octet, but an extra one subnet is created to add sixteen subnets.